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This Invention relates to a folding utility cart for general use that folds into a compact shape for ease of transportation and storage. Conventional carts are made from a variety of materials, including metal, wood, and plastic, and typically have a flat bed with raised sides. Wheels are typically mounted to the underside of the bed by means of brackets, with the front wheels customarily connected to a forward extending handle and mounted for steerability. While these carts are generally sturdy and can stand up to heavy use for extended periods of time, they are large and generally difficult to transport in vehicles, particularly modern vehicles with relatively small trunks. The overall volume occupied by traditional carts can render them difficult and space consuming to store.
Various hand trucks, carts, wagons, creepers, and the like have been hinged in order to allow them to be folded for storage. See, e.g., Martin, U.S. Pat. No. 6,095,532; Crowell, U.S. Pat. No. 5,857,695; Miles, et al., U.S. Pat. No. 5,611,552; DeWijn, U.S. Pat. 4,398,736; Olsson, U.S. Pat. No. 3,985,372; and Hoff, U.S. Pat. No. 3,822,069. While the methods divulged in these patents have been somewhat effective for flat carts, their arrangements are not fully successful with respect to carts having side rails, and none of them are directed to such a cart. Greenberg, U.S. Pat. No. 4,957,306 discusses a two-wheeled lawn cart with sides that fold down over the bed, but the method of folding discussed in the ""306 patent is only partially successful in creating a compact structure; the cart discussed in the ""306 patent is also substantially different than the present Invention. A folding child""s wagon with removable rails and wheels with a bed that folds in half is described by Shorter, U.S. Pat. No. 5,957,482. However, the folding mechanism is for the bed only, with a user forced to partially disassemble the wagon by removing the side rails and wheels in order to attain a fully compact structure. None of this prior work fully addresses the need for a fully collapsible cart, with all side and end rails as well as wheels folding into a compact package. Thus, there is a continuing need for an improved cart with side and end rails which is sturdy and which is foldable as a complete unit into a compact package for efficient storage. The present Invention answers those needs.
In accordance with the present Invention, a folding cart having both an operative position for use as well as a folded position for storage is described. The cart includes four major sets of components: the frame, which also forms the bed; the side and end rails; the wheel assemblies; and the handle, which also serves to lock the cart in its folded position. The frame is divided into forward, middle (or main), and rear frame sections. The forward and rear frame sections are defined generally as a planar structure defined by and comprising forward, rear, left, and right members with zero or more reinforcing members and a floor member attached to the upper side of the frame section. The forward and rear members of the forward and rear frame sections should be substantially parallel to each other, but do not need to be of equal lengths, such that the structure defined may be non-rectangular. The middle frame section, however, is defined generally as a planar, rectangular structure defined by and comprising forward, rear left, and right members with zero or more reinforcing members and a floor member attached to the upper side of the frame section. The reinforcing members extend across the shape defined by the forward, rear, left, and right members and are attached at their ends to any two of those members. The rear edge of the forward frame section is rotatably connected to the forward edge of the middle frame section, and the forward edge of the rear frame section is rotatably connected to the rear edge of the middle frame section. By this arrangement, in the folded position, the forward and rear frame sections fold to the top surface of the middle frame section. In the unfolded, operative position, the forward, middle, and rear frame sections form a plane. The left and right members of each frame section are hollow, forming a tube down each side of each frame section. Furthermore, manually articulable spring-loaded locking pins are present at each end of both the left and right members of the middle frame section. Each locking pin may be manually retracted and locked back into its respective frame member end, and when released, each locking pin extends from the end of its respective frame member end. In the unfolded position, the locking pins are released and extend into the respective contiguous left or right side member of the forward or rear frame section, thereby providing stability and great mechanical strength to the unfolded frame.
The side and end rails are also foldable. The forward end rail is rotatably connected at its lower edge to the forward edge of the forward frame section such that it folds from a raised position perpendicular to the frame into a position coplanar with the frame. Similarly, the rear end rail is rotatably connected at its lower edge to the rear edge of the rear frame section such that it too folds from a raised position perpendicular to the frame into a position coplanar with the frame. In a departure from customary practice, the left and right side rails do not fold into a position coplanar with the frame sections; rather, each side rail is divided into three sections; a forward side rail, middle side rail, and rear side rail. The rear edge of the forward side rail is rotatably connected to the forward edge of the middle side rail, and the forward edge of the rear side rail is rotatably connected to the rear edge of the middle side rail. The lower edge of the left middle side rail is non-rotatably connected to the left edge of the middle frame section such that the plane defined by the left middle side rail is substantially perpendicular to the plane defined by the middle frame section. The lower edge of the right middle side rail is non-rotatably connected in the same fashion to the right edge of the middle frame section. By this arrangement, the forward and rear side rails on each side may rotate from a position along the corresponding side edge of the corresponding forward or rear frame section into a position along the corresponding edge of the middle frame section and flush with the corresponding middle side rail.
The present Invention also includes two dual wheel assemblies, a forward dual wheel assembly and a rear dual wheel assembly. Each dual wheel assembly is substantially identical to the other, but the methods differ for attaching each wheel assembly to the lower surface of the frame. The rear dual wheel assembly is connected to the lower surface of the rear frame section in a fixed position; the forward dual wheel assembly, however, is rotatably connected to the lower surface of the forward frame section. This arrangement allows the forward dual wheel assembly to be used to steer the cart. Each dual wheel assembly includes a pair of wheels, each rotatably connected to a wheel bracket via a wheel axle. Each wheel bracket is rotatably connected by a pivot to one end of a dual wheel assembly bracket, which is connected to the lower frame as described. The dual wheel assembly bracket includes two wheel bracket locking pins, with one locking pin corresponding to each of the wheel brackets. By use of the locking pins, the wheels can be locked in two or more positions, including the fully folded and fully unfolded positions.
Finally, the present Invention includes a handle by which a user may pull the cart, which also serves to lock the Invention into the folded position. The handle is attached at one end to the forward dual wheel assembly""s dual wheel assembly bracket. The manner of attachment is such that the handle is rotatable in the vertical plane, but not in the horizontal plane. The handle is divided into three segments, including a handgrip, a middle segment, and an attachment segment, with the attachment segment actually attached to the forward dual wheel assembly. The attachment segment is rotatably connected to the middle segment; both the attachment segment and middle segment comprise tubes of identical cross-section. Furthermore, a locking mechanism is set in the middle segment such that when the attachment segment and middle segment are rotated into a linear, coaxial position, the two segments are locked into this position. The locking mechanism has a manual control allowing the user to release this lock when the Invention is being folded. The handgrip is attached coaxially to the middle segment and is of smaller cross-sectional dimension than the middle segment, such that the attachment end of the handgrip extends inside the middle segment. The handgrip may slide within the middle segment, and is retained in the middle segment by means of a spring such that a user may slide the handgrip out a short distance, but may not remove the handgrip from the middle segment. This ability to slide the handgrip out a short distance is important because it allows the user to latch the handgrip around the Invention in the folded position. After passing from the middle segment, the handgrip bends to a position substantially perpendicular to the line formed by the central axis of the middle segment. The bent portion of the handgrip is of a suitable size for a person to pull on it with one hand. The terminal end of the handgrip is attached to a lip plate, which, in the folded position, holds the handgrip in place around the rear end of the folded Invention.